Investigators probing the cause of Thursday’s crash have ruled out mechanical and infrastructure failure.

They are looking at the possibility of operator error at this point. One of the trains was parked on the outbound tracks when the other struck it from behind. WBZ-TV spoke with family members of the man who was operating the train that was struck.

WBZ-TV’s Jim Armstrong reports

“We saw him walking on the platform on the TV and that’s how we knew it was his train,” said Nancy Perno the operator’s mother. “All he said was the bang was so bad, they were stopped and the bang was so bad, and the people were bouncing off the seats and everything.”

Officials say there was nothing to indicate that drugs or alcohol played any role in the crash. They also say they do not believe the conductor in the moving train was using a cell phone. They are looking at the possibility of whether that driver may have been distracted.

“This was not his fault and it had nothing to do with him. He was in the wrong place at the wrong time,” says the wife of the operator whose train was hit. “He really wants to be home. He expected to do his day and come home as he does every night, and it’s been tough on him, tough on all of us.”

In a strange twist, the conductor blamed for causing the crash was supposed to receive a safe driver award on Friday. The MBTA noted that he had a previously flawless record.